Drive system



E. w. KELLOGG DRIVE-SYSTEM Filed Feb. 18, 1955 Sept. 14, 1937.

CASE

3/ J2 22 Luz 27 25 INVENTOR ATTORNEY Patented Sept. 14, 1937 r4 2,092 883 UNITED STATES PATENT OFFICE DRIVE SYSTEM Edward W. Kellogg, Moorestown, N. J., assignor to Radio Corporation of America, a corporation of Delaware Application February 18, 1935, Serial No. 7,059

Claims. (01; 74-411) This invention relates to drive systems suitable flexibly supported between the driving and. driven for the operation of phonographs, sound picture members, recorders and. reproducers and other types of Fig. 2 illustrates the application of the invenapparatus which are required to function at a tion to a worm gear drive y and 5 substantially constant speed. It has for its prin- Fig. 3 illustrates a modification of the arrangecipal object the provision of an improved conment of Fig. 1. stant speed drive system wherein the driving, The arrangement of Fig. 1 includes a driving damping and other applied forces are so balanced em er ll W ch s eared to a d ven membe .with respect to one another as to enable the H through an intermediate pinion l2. Damping driven member to be operated uniformly and in of the driven member II is eifected by a viscous l0 synchronism with associated apparatus. brake member l3 supp 011 an arm l4 PiVOted There have been provided in the past various at its lower end to a lever l5 which is p vo d at types of drive systems including mechanical filits left hand end to a stationary support l6 and at ters wherein a continuous brake load is applied a point inte ed a e its e to the pp IT t th driv element and the driving torque is of the pinion l2. It will be observed that the 15 applied through a spring. The primary pursupport I1 is itself supported through a spring pose of this brake load has been to provide dampand is provideda s lower e d Withti dash ing for preventing hunting or oscillation of the p v drive system at its natural vibration frequency. W t t arrangement j described the pinion 1 It may also provide a desirable mechanical im- I2 is evidently free to mOVe a limited distance 20 pedance to resist speed fluctuations especially in tangentially against e resilient force Of the cases where the moment of inertia is inadequate. Spring If there are Speed fi CtU O S n the If the moment of inertia is low, the filtering sysdriving y s imp f n n th driv tem, of course, becomes equivalent to an elecgears the pinion moves back and forth and tends trical filter having only capacity and resistance. to transmit a ant torque. If the load on 25 A practical difficulty encountered in the use of the driven member increases the D h OII Will tend mechanical filters employing a continuous brakto move downwardly. If a V us da p 0 ing action is that the deflection of the driving braking force is ppli o t driv n member H spring tends to become uncertain and is likely to produce chanic impedance Provide to be different under starting and running condampihgthis. brake W presumably con ute t e 30" ditions thus making it impossible to maintain the principal load Variations in friction u o dri m t in exact synchronism t assoexample, to change in viscosity of the brake lubriciated apparatus. A possible solution of this difcent with temperature would cause the brake ficulty i disclosed i my copending application load to change. It should be noted that the brake.

Serial No. 704,725, filed December 30, 1933, which shoe I3 is connected to the vab p ion l2 35 matured into Patent Number 2,050,613, for a through levers l5 and IT in Such a r that clutch or brake mechanism Opel-able t deliver to the force reacted on the brake shoe neutralizes 1 the driven member a torque which is substantially the tendency of the drag on the driven member constant irrespective of variations in the primary to move the pinion from its neutral Positiontorque applied to the drive system. In d, Since the force tending to displace the axis of the 40 ance with the present invention, the aforemenpinioh is twice that @Xerted at the Periphery of tioned difiiculty is avoided by applying to a memthe dnven gear the through which her flexibly Supported between the driving and brake shoe and movable 131111011 are connected driven members a force which is derived from a i be ifi g g fig' g E 2' or driven member and which acts against the forces she; be light in, i, to avoid impairing the tending to move the flexibly supported intermetermg action The dash pot '9 shown as diate F neutral posmon' nected to the movable idler or pinion I2 is desir- The mventlon 1 better understood m able but not an essential feature of the system. 50 the followmg descnptlon when conslderedm It will be understood that a spring similar tothe connection with the drawing, and its scope will be spring 13 may be inserted in t coupling p n Out in the appended Claims: tween the idler l2 and the intermediate pivot Referring to the drawing: point of the lever l5. Fig. 1 illustrates a system wherein a pinion is The arrangement of Fig. 2 includes a motor 20' 55 which is coupled to the driven member I I through a coupling 2|, a worm gear 22 and a cooperating gear 23. Arranged to cooperate with the driven member H is a viscous brake l3 which is coupled 5 to the worm gear 22 through levers 24 and 25, a spring 26 and a worm gear shaft 21. The lever 25 is pivoted to a stationary support 28. The lever 24 is pivoted to a point intermediate the ends of the lever 25 and is provided at its end with a dash pot 29. A dash pot 30 is provided in connection with a bearing of the shaft 2?. The coupling 2| includes a spring 3| mounted in a collar 32 which is fixed to the shaft 21. A shaft 33 of the motor 2i! is splined into the collar 32 thus permitting the worm gear 22 to move axially against the action of the spring 3|. The connection of the brake shoe 13 to the spring 26 is such that a change in brake load causes an axial movement of the shaft 2'! thus changing the spring compression and applying a force which offsets the change in force exerted through the gear teeth. The mean working position of the worm is therefore unaltered. The gears 22 and 23 and their associated parts may be mounted in 25 a container containing oil or other suitable lubricating material.

The arrangement in Fig. 3 is similar to that of Fig. 1 in that a flexibly supported pinion I2 is interposed between the driving member l0 and the driven member II. In this modification of the invention, however, there are associated with the driven member H a plurality of governors 34 of the usual phonograph type mounted on a ring 35 and coupled tothe driven member H through 35 rollers 35. It will be noted that the support I! of I the pinion i2 is provided at its lower end with a l dash pot 37 and is coupled through a crank arm 38 and lever 39 to the ring 35. A dash pot 40 is coupled to the ring through rod 4 l. 40 As will be readily understood, the load of the governors 34 will cause the ring to rotate and thereby stretch the spring l8 sufficiently to exert on the pinion l2 a force equal to the reaction of the governor load on the axis of the pinion. The pinion therefore, tends to remain in a fixed position which is determined by a spring 42 associated with the dash pot 31. The purpose of the governors in holding the speed constant would be defeated if the governor ring could move with appreciable rapidity. The dash pot 40 prevents this. Stops 43 are arranged to limit the movement of the pinion. When operation of the apparatus is initiated the position of the pinion is limited by one of the stops. When the governor brakes take hold the ring will slowly move in the direction of rotation of the main gear thereby stretching spring [8 and tending to bring the pinion back to its normal position.

Having thus described my invention, I claim:

1. The combination of a driven member, a worm resiliently supported for axial movement and arranged to drive said member, damping means associated with said driven member, and means for applying the reaction force of said damping means to said worm for restoring said worm to its neutral position.

2. The combination of a driven member, a worm resiliently supported for axial movement and arranged to drive said member, damping means associated with said driven member, a linkage for applying the reaction force of said damping means to said worm, and means for damping the movement of said linkage.

3. The combination of a driven member, a worm resiliently supported for axial movement and arranged to drive said member, damping means associated with said driven member, a linkage for applying the reaction force of said damping means to said worm, and means for damping the axial movement of said worm.

4. In combination a driving member, a driven member, a coupling member interposed between said members, means flexibly supporting said coupling member, a damping member in frictional cooperative relation with said driven member whereby it is urged in the direction of motion of the said driven member, and means connecting said clamping member and said supporting means whereby said damping member and said coupling member are maintained in equilibrium during operation.

5. In combination a driving member, a driven member, a coupling member interposed between said members, a friction member in cooperative relation with said driven member, and adapted to be urged in the direction of movement thereof, means yieldably supporting said friction member, damping means connected to said supporting means and means connecting said supporting means to said coupling member, whereby the force produced by the friction of said friction member against said driven member is balanced against the force tending to move said coupling member.

EDWARD W. KELLOGG. 

